1. Technical Field
The present disclosure relates to actuators, and particularly, relates to a piezoelectric actuator.
2. Description of Related Art
Many camera modules have zooming and/or autofocus functions. A typical camera module employs a piezoelectric actuator to drive a lens unit to move along an optical axis to perform the zoom/focusing functions. The piezoelectric actuator includes a fixed member, a movable member movably received in the fixed member, and a piezoelectric member fixed on the fixed member and contacted with the movable member. The piezoelectric actuator further employs two magnets for providing a preload force on the piezoelectric member and the movable member to drive the piezoelectric member to be in contact with the movable member. One of the magnets is fixed on a side the fixed member, and the other of the magnets is fixed on the movable member.
However, the magnet is heavy and a density of the magnet is much larger than that of the movable member, if fixed on a side of the movable, the magnet will make the central axis of the movable member deflected relative to the optical axis.
What is needed therefore is a piezoelectric actuator addressing the limitations described.